<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
    .coupon {
    width: 300px;
    height: 100px;
    cursor: pointer;
    line-height: 100px;
    margin: 50px auto;
    text-align: center;
    position: relative;
    background: radial-gradient(circle at right bottom, transparent 10px, skyblue 0) top right /50% 51px no-repeat,
    radial-gradient(circle at left bottom, transparent 10px, skyblue 0) top left / 50% 51px no-repeat,
    radial-gradient(circle at right top, transparent 10px, skyblue 0) bottom right / 50% 51px no-repeat,
    radial-gradient(circle at left top, transparent 10px, skyblue 0) bottom left / 50% 51px no-repeat;
    filter: drop-shadow(2px 2px 2px rgba(0, 0, 0, .2));
    }
    .coupon span {
    display: inline-block;
    vertical-align: middle;
    margin-right: 10px;
    color: red;
    font-size: 50px;
    font-weight: 400;
    }
    </style>
</head>
<body>
    <p class="coupon">
        <span>200</span>优惠券
    </p>
</body>
</html>